DETERMINANT FACTORS RELATED TO THE VARIATION IN HORIZONTAL VELOCITY OF THE BODY CENTRE OF MASS IN BUTTERFLY

INTRODUCTION: According to Persyn et al. (1995) in the global strokes only the resultant impulse on the body, which is the difference between propulsion and drag forces, can be calculated from one phase to another. Therefore, the horizontal velocity variation of the body centre of mass (CMbody) in a stroke cycle must be calculated. When the horizontal velocity of the CMbody varies considerably, the swimmer has to overcome during each stroke cycle high hydrodynamic drag forces, due to the high peak velocity

Social and cultural contexts change but intelligence persists as incisive to explain children’s academic achievement

The intelligence is a well established predictor of school achievement. Although school failure/success can be explained by cognitive variables, socio-familial variables can also have an impact. Since these variables haven’t been so systematically investigated together, the present study aims to consider both variables to understand their causal roles in academic achievement. With a sample of 376 Portuguese children aged 6 to 10 years, a path analysis was carried out based on a prior analysis to search for causal relationships between intelligence and socio-familial variables to explain children’s academic achievement. The results point to intelligence as a major influence on school performance, combined with socio-familial variables (directly: community, type of school, mother's education and school year; and indirectly: socioeconomic status and father’s education level). Practical implications were discussed concerning the relevance of the investigated variables in explaining academic achievement of children.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Fundação para a Ciência e Tecnologia, IP (FCT) and the POCH/FSE under Grant SFRH/BD/85110/2012 to Ana Filipa Alves

Contraceptive Choices Pre and Post Pregnancy in Adolescence

STUDY OBJECTIVE: The main aim of this study is to evaluate the impact of adolescent pregnancy in the future contraceptive choices. A secondary aim is to verify whether these choices differ from those made after an abortion. DESIGN: Retrospective study. SETTING:Adolescent Unit of a tertiary care center. PARTICIPANTS:212 pregnant teenagers. INTERVENTIONS: Medical records review. MAIN OUTCOME MEASURES:Intended pregnancy rate and contraceptive methods used before and after pregnancy. For contraceptive choices after pregnancy we considered: Group 1 - teenagers who continued their pregnancy to delivery (n = 106) and Group 2 - the same number of adolescents who chose to terminate their pregnancy. RESULTS: The intended pregnancy rate was 14.2%. Prior to a pregnancy continued to delivery, the most widely used contraceptive method was the male condom (50.9%), followed by oral combined contraceptives (28.3%); 18.9% of adolescents were not using any contraceptive method. After pregnancy, contraceptive implant was chosen by 70.8% of subjects (P < .001) and the oral combined contraceptives remained the second most frequent option (17.9%, P = .058). Comparing these results with Group 2, we found that the outcome of the pregnancy was the main factor in the choices that were made. Thus, after a pregnancy continued to delivery, adolescents prefer the use of LARC [78.4% vs 40.5%, OR: 5,958 - 95% (2.914-12.181), P < .001)], especially contraceptive implants [70.8% vs 38.7%, OR: 4.371 - 95% (2.224-8.591), P < .001], to oral combined contraceptives [17.9% vs 57.5%, OR: 0.118 - 95% CI (0.054-0.258), P < .001]. CONCLUSION:Adolescent pregnancy and its outcome constitute a factor of change in future contraceptive choice

Azadirachtin on Oligonychus yothersi in yerba mate Ilex paraguariensis.

The red mite Oligonychus yothersi is one of the main pests of yerba mate in Brazil The damage this mite causes leads to leaf drop and decreased production. There are no registered acaricides for use in yerba mate; thus, laboratory and field experiments were performed to evaluate the effect of azadirachtin (Azamax ® , 250mL 100L -1 ) for the control of the red mite in yerba mate. In the laboratory, azadirachtin was applied to yerba mate leaf disks before (residual contact) and after (direct contact) infestation with 15 newly emerged red mite adult females. The effect of azadirachtin on mite behavior was evaluated in arenas with treated and untreated yerba mate leaves, and the number of mites in both areas was recorded. Ovicidal action was evaluated by applying azadirachtin to eggs and recording egg hatching. In the field, two applications of the product were performed (1L spray liquid plant-1) with a 7-day interval. The numbers of living mites were evaluated at 7, 14 and 21 days following the first application on randomly collected leaves. It was observed 86.6 and 91.4% of mortality following 24h of residual and direct contact, respectively. Repellent (62% of individuals leaving the treated area) and ovicidal (98.9% decrease in egg hatching) effects were also observed. The mite population in the yerba mate crop field had decreased by 59.6% at 14 days after the first application of azadirachtin. The results show the potential of azadirachtin for the control of O. yothersi in yerba mate in Brazil. Key words: neem, alternative control, yerba mate pest. O ácaro Oligonychus yothersi é uma das principais pragas da cultura da erva-mate. Seus danos levam à queda das folhas e redução da produção. Não há acaricidas registrados para uso na erva-mate e por isso foram realizados experimentos em laboratório e a campo para avaliar o efeito da azadiractina (Azamax®, 250mL 100L-1), visando ao controle da espécie na cultura da erva mate. Em laboratório, o produto foi aplicado em discos de folha de erva-mate antes (contato residual) e depois (contato direto) da infestação com 15 fêmeas adultas recém-emergidas do ácaro vermelho. A ação do produto no comportamento do ácaro foi avaliada em arenas com folhas de erva-mate tratadas e não tratadas, registrando-se o número de ácaros em ambas as áreas. Além disso, a ação ovicida foi avaliada, aplicando-se o produto sobre ovos e registrando a sua eclosão. No campo, foram realizadas duas aplicações do produto (1L de calda planta-1), espaçadas sete dias. Avaliou-se o número de ácaros vivos, aos 7, 14 e 21 dias após a primeira aplicação, em folhas coletadas aleatoriamente. Observou-se ação acaricida (86,6 e 91,4% de mortalidade após 24h, respectivamente, por contato residual e direto; repelência (62% dos indivíduos abandonando a área tratada) e ação ovicida (redução de 98,9% na eclosão). Na lavoura de erva-mate, a redução populacional do ácaro foi de 59.6% aos 14 dias após a primeira aplicação do produto. Os resultados demonstram o potencial de emprego da azadiractina para o controle de O. yothersi na cultura da erva-mate.Palavra-chave: nim, controle alternativo, praga da erva-mate

Cognitive performance in childhood: mother and urban environment make the difference

Apesar das controvérsias sobre o conceito e a avaliação da inteligência, o desempenho cognitivo assume um papel fundamental no contexto educativo e são múltiplos os fatores que lhe estão associados. Este estudo toma uma amostra aleatória e representativa de 1201 crianças do 2.º ciclo do ensino básico de escolas públicas portuguesas, com idades entre 9 e 14 anos. Discute-se o impacto das variáveis sociofamiliares (profissão da mãe e do pai, escolaridade da mãe e do pai e meio de pertença urbano vs rural). Os resultados destacam a relevância dessas variáveis para a explicação do desempenho cognitivo dos alunos, especialmente a escolaridade da mãe e o meio urbano de proveniência. Apresentam-se considerações práticas voltadas à equidade do sistema educativo.Despite the controversies over the concept and evaluation of intelligence, cognitive achievement plays a fundamental role in educational context, and multiple factors are related to it. The current study uses a random and representative sample of 1201 2nd grade children from Portuguese public schools, between 9 and 14 years old. This study aims to discuss the impact of social and familial variables (mother and father’s jobs, mother and father’s educational level, and urban or rural environment of belonging). The results highlight the importance of social and familial variables as an explanation to students’ cognitive achievement, with great relevance to mother’s educational level and urban environment of belonging. Practical considerations aiming a better equity in educational system are presented.info:eu-repo/semantics/publishedVersio